Question

Why do transition elements form complex compounds?

Answer 1

transition elements have empty d-orbital and they posses variable oxidation states therefore the transition elements form complex compounds .

Answer 2

transition-metal ions form coordination complexes because they have empty valence-shell orbitals that can accept pairs of electrons from a Lewis base. They must contain at least one pair of non bonding electrons that can be donated to a metal ion.Transition metals are found in the middle of the periodic table.  Most of these compounds are ionic or network solids, but there are some molecular compounds, too, in which different atoms are arranged around a metal ion. These compounds are called transition metal complexes or coordination complexes.transition elements have empty d-orbital and they posses variable oxidation states therefore the transition elements form complex compounds .